Dura-Ace 10 speed and compact crankset on the same bike



I

ironlaku

Guest
I was told that "with minor modifications" one could easily swap between the
original Dura-Ace 10-speed (53/39) and a compact crankset.
I'd like to have a compact (50/34) for climbing in the Alps and keep the
original for the rest.

Does anybody know which compact crankset it could be and what the "minor
mods" are?

ironlaku
 
I don't think there are any compacts that fit the new style Dura Ace 10
speed BB. So you would have to swap the BB as well. Also the standard front
derailleur might work if you can mount is low enough to the 50 chainring, or
else you will have to get a compact front like the IRD. I had problems with
the IRD on a Scott CR1 since it wouldn't mount low enough so the chain would
derail when shifting up to the big ring. I ended up with a modified campy
compact front that I had to grind down some pivot points and cage to make
clearance for the chain when on the small ring and largest cog.

cel


"ironlaku" <[email protected]> wrote in message
news:[email protected]...
> I was told that "with minor modifications" one could easily swap between

the
> original Dura-Ace 10-speed (53/39) and a compact crankset.
> I'd like to have a compact (50/34) for climbing in the Alps and keep the
> original for the rest.
>
> Does anybody know which compact crankset it could be and what the "minor
> mods" are?
>
> ironlaku
>
>
>
 
ironlaku wrote:
> I was told that "with minor modifications" one could easily swap

between the
> original Dura-Ace 10-speed (53/39) and a compact crankset.
> I'd like to have a compact (50/34) for climbing in the Alps and keep

the
> original for the rest.
>
> Does anybody know which compact crankset it could be and what the

"minor
> mods" are?
>
> ironlaku


Use any compact crankset..and the only thing ya gotta do is lower your
front der....
 
"Qui si parla Campagnolo" <[email protected]> wrote:

>
>ironlaku wrote:
>> I was told that "with minor modifications" one could easily swap

>between the
>> original Dura-Ace 10-speed (53/39) and a compact crankset.
>> I'd like to have a compact (50/34) for climbing in the Alps and keep

>the
>> original for the rest.
>>
>> Does anybody know which compact crankset it could be and what the

>"minor
>> mods" are?
>>
>> ironlaku

>
>Use any compact crankset..and the only thing ya gotta do is lower your
>front der....


And take 2 links outta your chain...
--dt
 
Doug Taylor wrote:
> "Qui si parla Campagnolo" <[email protected]> wrote:
>
> >
> >ironlaku wrote:
> >> I was told that "with minor modifications" one could easily swap

> >between the
> >> original Dura-Ace 10-speed (53/39) and a compact crankset.
> >> I'd like to have a compact (50/34) for climbing in the Alps and

keep
> >the
> >> original for the rest.
> >>
> >> Does anybody know which compact crankset it could be and what the

> >"minor
> >> mods" are?
> >>
> >> ironlaku

> >
> >Use any compact crankset..and the only thing ya gotta do is lower

your
> >front der....

>
> And take 2 links outta your chain...
> --dt


Depends. I just put one on a DA bicycle, with a 12-25, and he wanted to
also swap at times for a 12-28...no links removed.

If you swap to a 11-23, yes, but not always.
 
1. Any compact crankset

2. A new BB. Nashbar sells a disposable ISIS for $15

3. If you have a braze-on, you may need to file/grind the slot so you
can get the derailleur low enough

4. As derailleurs go, your current one is probably fine. I started with
a 105 triple and replaced it with a Centaur double. It may be Campy vs
Shimano cage shaping, but it works better with the standard double than
it did with the triple.

5. No matter how good you think you are at setting a front derailleur,
something like a "JumpStop" or "ThirdEye Chainwatcher" is worth
considering. On occasions, I still had the chain drop off to the
inside. If it does this, you probably can't rescue it with shifter
manipulation. You have to stop and get off. Not fun in the Alps!

ironlaku wrote:
> I was told that "with minor modifications" one could easily swap between the
> original Dura-Ace 10-speed (53/39) and a compact crankset.
> I'd like to have a compact (50/34) for climbing in the Alps and keep the
> original for the rest.
>
> Does anybody know which compact crankset it could be and what the "minor
> mods" are?
>
> ironlaku
>
>
>
 
On 14 May 2005 06:30:59 -0700, "Qui si parla Campagnolo"
<[email protected]> wrote:
>
>Depends. I just put one on a DA bicycle, with a 12-25, and he wanted to
>also swap at times for a 12-28...no links removed.
>
>If you swap to a 11-23, yes, but not always.


Whatever. I'm running a 12-26 SRAM, and the chain was too lack in the
lower gears until I removed the links.

I also agree with the poster who recommended a chain stopper. I'm
using a Deda Dog Fang, which to my eye is more elegant than some
others on the market. Works like a charm keeping the chain from
falling off to the inside. The jump from 50 to 34 is big.
http://www.dedaelementi.com/cat_accessori.asp

Adjusting the big ring limit is another story.
 
"Doug Taylor" <[email protected]> wrote in message
news:[email protected]...
> On 14 May 2005 06:30:59 -0700, "Qui si parla Campagnolo"
> <[email protected]> wrote:
>>
>>Depends. I just put one on a DA bicycle, with a 12-25, and he wanted to
>>also swap at times for a 12-28...no links removed.
>>
>>If you swap to a 11-23, yes, but not always.

>
> Whatever. I'm running a 12-26 SRAM, and the chain was too lack in the
> lower gears until I removed the links.
>

In contrast, I went from 51-39 upfront with 13x26 in the back to 48-36 in
the front and the same 13x26 in the back. Same chain, same length - no links
removed, no problem!
 
On Fri, 13 May 2005 07:20:40 +0200, "ironlaku" <[email protected]> wrote:

>Does anybody know which compact crankset it could be and what the "minor
>mods" are?


Any crankset with the proper bottom bracket.
 
On 14 May 2005 06:30:59 -0700, "Qui si parla Campagnolo"
<[email protected]> wrote:

>Depends. I just put one on a DA bicycle, with a 12-25, and he wanted to
>also swap at times for a 12-28...no links removed.
>
>If you swap to a 11-23, yes, but not always.


I have found that with compact cranks, sizing the chain as long as
possible makes for better shifts and less chain deraillment on inside
of 34.

I hypothesize that whan the front derailleur pushes on the chain, a
looser/bigger chain creeps up the shift assist faster. I do know that
it works. Therefore, I size the chain so that when in the
small/small, the chain doesn't drag on the bottom of the rear
derailleur. Also, the 'b' tension has to be able to adjust so that
the pulley doesn't contact the largest ring in the small/big.
 
On Sat, 14 May 2005 13:49:15 GMT, richard
<[email protected]> wrote:

>3. If you have a braze-on, you may need to file/grind the slot so you
>can get the derailleur low enough


I worded on a Trek OCLV and the derailleur mount was so high that even
major filing wouldn't have let the front derailleur cage down enough.
The derailleur slot piece looks replaceable and Trek may make several
versions. I know on another OCLV, I just lowered the derailleur with
plenty of space left.
 
On Sun, 15 May 2005 19:37:55 GMT, Paul Kopit
<[email protected]> wrote:

>On 14 May 2005 06:30:59 -0700, "Qui si parla Campagnolo"
><[email protected]> wrote:
>
>>Depends. I just put one on a DA bicycle, with a 12-25, and he wanted to
>>also swap at times for a 12-28...no links removed.
>>
>>If you swap to a 11-23, yes, but not always.

>
>I have found that with compact cranks, sizing the chain as long as
>possible makes for better shifts and less chain deraillment on inside
>of 34.
>
>I hypothesize that whan the front derailleur pushes on the chain, a
>looser/bigger chain creeps up the shift assist faster. I do know that
>it works. Therefore, I size the chain so that when in the
>small/small, the chain doesn't drag on the bottom of the rear
>derailleur. Also, the 'b' tension has to be able to adjust so that
>the pulley doesn't contact the largest ring in the small/big.


Interesting. I shortened the chain and had to add a chain stopper to
keep the chain from falling off to the inside. Perhaps a mistake...

As for the big ring limit, I had to swap a longer tension screw with
the stock one in my Ultegra derailleur in order to keep the chain from
falling off the outside of the big ring on the upshift. The stock
screw was just a tad too short.

Would chain length affect the up shift as well?
 
Paul Kopit wrote:
> On Sat, 14 May 2005 13:49:15 GMT, richard
> <[email protected]> wrote:
>
> >3. If you have a braze-on, you may need to file/grind the slot so

you
> >can get the derailleur low enough

>
> I worded on a Trek OCLV and the derailleur mount was so high that

even
> major filing wouldn't have let the front derailleur cage down enough.
> The derailleur slot piece looks replaceable and Trek may make several
> versions. I know on another OCLV, I just lowered the derailleur with
> plenty of space left.


Trek now makes a longer, replaceable front der hanger for compact
cranks...
 

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